To the Editor In a propensity score–matched cohort of 578 patients from 4 observational cohort studies, Dr Kuramatsu and colleagues showed that evacuation of medium-sized intracerebellar hematomas (approximate volume, 20 cm³) was not associated with better functional outcome.¹ Assessing treatment effectiveness in observational data is challenging because treatment decisions are based on patient characteristics that also are typically predictive of outcome, causing confounding by indication. Although the authors addressed this potential bias with propensity scores, we would like to emphasize the possibility of residual confounding.

中文翻译：

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小脑颅内出血的治疗性观察研究中的未测混杂。

给编辑在从4个观察队列研究578名患者倾向评分匹配队列，Kuramatsu博士和他的同事表明中型小脑内血肿的疏散（近似体积为20cm ³）中的溶液不与更好的功能预后相关联。¹在观察数据中评估治疗效果具有挑战性，因为治疗决策基于患者特征，通常也可预测结果，从而因适应症而引起混淆。尽管作者使用倾向评分解决了这种潜在的偏见，但我们还是要强调残留混杂的可能性。